COST OF REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cost of Revenue [Abstract]
Compensation and benefits	$ 65,063	$ 69,326
Outside fees and services	71,803	53,247
Reimbursable expenses	15,454	31,956
Technology and telecommunications	9,940	11,893
Depreciation and amortization	6,603	6,404
Total	$ 168,863	$ 172,826